Robert P
Acorn PAg.About the author:
In 1999 Robert Acorn was an agrologist working for the Animal
Industry Division of Alberta Agriculture. The
article below first appeared as a joint presentation with veterinarian
Dr. Carla Lindahl at the 1999 Alberta Elk association Conference in
Jasper , Alberta and was then published in The Tracker magazine who
have allowed me to include it on this website.

As with many
things we do, knowledge is often the key to success. Producers who
develop a diverse knowledge and understanding of elk production,
requirements for health and related issues, and who work in partnership
with their veterinary practitioner and other specialists, will
generally be those most successful at elk farming. The following
article will help add to the knowledge you now have on keeping elk
healthy.

There are about
850 species of ticks world wide, many of which carry
and spread serious diseases to man and animals. Ticks belong to the
same
group of animals as spiders and lice. They have 8 legs as adults and go
through several stages of development from egg to adult. The Winter
tick
(Dermacentor albipictus) is
common throughout
North America. Moose, elk and deer are normal hosts of the Winter tick,
however other livestock can also be affected. It is the Winter tick
which
commonly affects elk on farms.

Life Cycle

The Winter tick
is a "one host" parasite,
completing its full development from larvae to adult on one cervid
host.
It has 3 distinct life stages. Eggs on the ground hatch in August and
September.
The tick larvae ascends to the tops of grasses and bushes in September
and October, waiting for the opportunity to attach to an animal it
comes
in contact with. In Alberta, peak numbers of larvae coincides with the
breeding activity of moose and elk. Once on a host, the tick larvae
attaches
to the skin, take a blood feed and changes into a immature tick or
nymph
within about 21 days. The nymph remains on the host but does not blood
feed again until January or February, at which time it changes to an
adult
tick. The adult tick remains on the same host without further feeding
until
March or April, at which time it engorges on blood, then mates and
drops
off its host. In about June, mature females deposit thousands of eggs
on
the ground.

The Winter tick
is not associated with
the spread of diseases like many other ticks because it lives its
entire
life on one animal. Other types of tick attack different animals each
time
they require a blood meal, thereby spreading viruses, bacteria and
other
pathogens. Ticks on elk farms are generally an aesthetic problem;
chewing,
biting and hair loss results in poor looking elk. Wild moose and elk
heavily
infested with Winter tick and emaciated and stressed by severe winter
conditions,
can die from anemia due to severe blood loss from tick feeding. An
adult
Winter tick is able to expand as it feeds on blood, allowing the tick
to
grow 200 or more times its normal size.

Clinical
signs

Ticks feeding
on elk cause considerable
irritation indicated by chewing, licking and rubbing. The initial signs
of a tick problem will show in October and November when tick larvae
begin
feeding. This is characterized by a disturbed hair coat along the top
of
the shoulders, lower neck and back. Ticks feed again during the January
through April period, once more causing irritation. Rubbing,
scratching,
and chewing results in hair loss on the lower neck and upper shoulders,
and a scruffy, unthrifty appearance.

Prevention

As with other
parasites, breaking the life
cycle is the key to prevention. Winter tick problems can be controlled
or minimized through pasture rotation and timely chemical treatment of
infected elk.

If possible, do not place elk on pastures
in September and October (when tick larvae are infecting elk) that had
tick infested elk in them the previous April and May (when adult ticks
are infecting pasture).

When fencing new pasture that has been
used
by wild game, especially native pasture containing trees and brush,
remove
your elk from this pasture during September and October.

If you notice tell-tale chew and lick marks
on the shoulders and backs of your elk in October, treat them as soon
as
possible, ideally about the first of November. Pour-on or injectable
parasite
control products will control ticks only if applied when ticks are
blood
feeding. The next opportunity to control ticks would be the next
feeding
period, about mid January. Pour-on treatments offer a longer residual
period
of control than injectable treatments.